At least 31 people have died across Uttar Pradesh due to the intense cold and three more were killed in road accidents because of dense fog, officials said on Tuesday. The cold wave, accompanied by heavy fog, has disrupted road, rail and air traffic across northern India and minimum temperature has dipped below normal at many places. Eight people died in eastern UP because of the inclement weather since Monday. Six died in the Avadh region, two each in Meerutand Kanpur, seven in Moradabad and six perished in Aligarh as the cold wave continued unabated. A mother and her son were killed when their car hit a stationary truck in dense fog in Sarojini Nagar area of Lucknow, police said. Abhishek Shukla, 40, and his mother Urmila, 62, were seriously injured when their car rammed into the truck on Monday night due to fog near Daroga Khera, they said. They were rushed to a hospital where doctors declared them dead, police said. Another man was killed and six others were injured when a SUV hit a car due to dense fog at Yamuna Expressway in Mathura. The incident took place on Monday night when the driver of the SUV, on his way to Agra, dashed into the car after colliding head-on with a roadways bus. The SUV driver could not see the bus coming from opposite direction due to dense fog and hit the car, police said.

In the mishap, SUV driver Rajesh, a resident of a Kanpur village, died and six persons from both the vehicles were seriously injured. The Met Office has said the cold wave condition would continue in the coming days. A drop in the mercury accompanied with a dense fog delayed trains, railway officials said. In Lucknow, more than 150 trains were delayed due to fog and poor visibility. Trains such as Punjab Mail, Saryu-Yamuna Express, New Delhi-Jalpaiguri Express, Kota-Patna Express, Sadbhavna Express, Kumbh Express, Vaishali Express, besides others, were delayed by 10-12 hours, a railway official told IANS. A state government spokesperson told IANS that all government aided and private schools in the state have been asked to remain shut till December 28. Delhi experienced a chilly and foggy Tuesday morning that affected at least 65 trains, arriving and departing from the city. An official of the Northern Railway said at least 54 trains coming to the city were running late, while 11 trains departing from Delhi were rescheduled due to dense fog. According to the Met Office, the visibility at 8.30am was 400 metres and humidity was 91%. The minimum temperature settled two notches below the season's average at 6 degrees Celsius. The Met office has forecast a chilly day ahead in the Capital. "The sky will remain clear throughout the day... Light fog will return in the evening," said an official of the India Meteorological Department. The day's maximum temperature is likely to hover around 17 degrees Celsius. Monday was the coldest December 22 in five years in Delhi as the minimum temperature dipped four notches below the season's average to 4.2 degrees Celsius, while the maximum settled at 15.8 degrees Celsius, six notches below the average.